This invention relates to indicator lights and particularly to power supplies for indicator lights. More particularly, the invention relates to a miniaturized isolated power supply for an indicator light.
Illuminated indicators, commonly referred to as indicator lights, are used in industrial control applications to signal the state of a remote piece of control apparatus. Indicator lights may be incorporated in pushbutton operated electrical switches. One or a few indicator lights may be located directly on an enclosure for electrical control apparatus or may be arranged in an array of indicator lights on a large control panel. The indicator light is connected to the power supply for the electrical control apparatus but contains its own power supply which commonly comprises a step-down transformer to provide reduced voltage for the light. Such power supplies typically use low frequency, bulky and heavy iron transformers, resulting in large, more expensive components and a need to dissipate significant power and heat. It is desirable to electrically isolate the light circuit at the secondary side of the transformer from the primary electrical supply. It is also desirable to provide a second input terminal to the indicator light for applying a test signal for the light. This second input necessitates the incorporation of a relay which increases the parts count and cost of the indicator light assembly.